Older Breaker Spring Charging Question

[adamscb]

Forum,

In the plant I work at there are a lot of older-style switchgear breakers (mostly Westinghouse) that have springs that you have to charge or discharge. Question i have is are these springs for just opening/closing the breakers, or are they used for the tripping function as well? If we forget to 'charge' the spring, will the breaker will not trip if it sees excess currents? Thanks

 

[Jraef]

No. The spring charge is only for CLOSING the breaker. When you close it, you are simultaneously charging the spring that opens it, whether that opening is from a fault trip or someone hitting the "Open" button.

 

[Tony S]

It does pay to “exercise” the breaker every couple of years to keep the trip mechanism free.

 

[wbdvt]

It does pay to “exercise” the breaker every couple of years to keep the trip mechanism free.

It also pays to do other maintenance on the breaker, such as replacing grease to avoid grease hardening, primary current injection to verify trip units settings, contact pressure, etc. What the manufacturer recommends for periodic maintenance.

 

[ATSman]

It also pays to do other maintenance on the breaker, such as replacing grease to avoid grease hardening, primary current injection to verify trip units settings, contact pressure, etc. What the manufacturer recommends for periodic maintenance.

Yes, we find that the majority of the problems with equipment such as air frame circuit breakers, ATSs, bolted pressure (Pringle) switches, etc are mechanical rather than electrical. Dried grease is the main culprit that prevents mechanisms (linkage bars, shafts, bearings) from operating smoothly and trip bars to stick and fail to reset. Stay away from petroleum based greases which will always dry up over time. We recommend using a synthetic based grease such as Mobiltemp SHC 32. It is a red grease that does not seem to harden like the others.

 

[Tony S]

Unfortunately switchgear only gets any TLC after something has failed. Before I retired I was constantly fighting an uphill battle to get finance for switchgear maintenance.

A 11kV breaker failed to trip, two guesses whose backside got kicked because of the damage and downtime?

 

[NewtonLaw]

Forum,

In the plant I work at there are a lot of older-style switchgear breakers (mostly Westinghouse) that have springs that you have to charge or discharge. Question i have is are these springs for just opening/closing the breakers, or are they used for the tripping function as well? If we forget to 'charge' the spring, will the breaker will not trip if it sees excess currents? Thanks

I agree with all the replies you got and to your question and especially with TonyS' comment about failing to trip. My experience with the Westinghouse and GE circuit breakers that use the closing spring to both close and charge the tripping springs can be a failure waiting to happen if not well maintained. Example, stiff grease or dirty grease on the mechanism used to charge the closing spring will also cause the spring to expend it's energy trying to overcome the additional friction of bad grease. In which case the breaker will end up not completely closed (not latched) however the main contacts will be closed and are being held in place due to the incomplete closure. In this condition, it will not trip until the closing spring pressure is released by manual trip. This can be problematic in that the CB trips but not at designed speed.

Hope this helps,

Newton Law

 

[kwired]

Unfortunately switchgear only gets any TLC after something has failed. Before I retired I was constantly fighting an uphill battle to get finance for switchgear maintenance.

A 11kV breaker failed to trip, two guesses whose backside got kicked because of the damage and downtime?

How many deaf ears heard the reply of "if you would have let me schedule the maintenance I wanted this likely wouldn't have happened"?

 

[Tony S]

How many deaf ears heard the reply of "if you would have let me schedule the maintenance I wanted this likely wouldn't have happened"?

Maintenance work is seen as a drain on company profits, a necessary evil. I’ve sat on both sides of the table, as maintenance supervisor and as factory production manager.

The only thing that matters is £ or $ in the company coffers. As factory production manager it was $.

 

[kwired]

Maintenance work is seen as a drain on company profits, a necessary evil. I’ve sat on both sides of the table, as maintenance supervisor and as factory production manager.

The only thing that matters is £ or $ in the company coffers. As factory production manager it was $.

Someone needs to learn that scheduled maintenance costs less then emergency maintenance usually does, especially on a component that will take the entire process down if it fails.